feat(speckit): integrate ux reference into workflows

Introduce a UX reference stage to ensure technical plans align with
user experience goals. Adds a new template, a generation step in the
specification workflow, and mandatory validation checks during
planning to prevent technical compromises from degrading the defined
user experience.

.specify/templates/ux-reference-template.md

@@ -0,0 +1,67 @@
+# UX Reference: [FEATURE NAME]
+
+**Feature Branch**: `[###-feature-name]`
+**Created**: [DATE]
+**Status**: Draft
+
+## 1. User Persona & Context
+
+*   **Who is the user?**: [e.g. Junior Developer, System Administrator, End User]
+*   **What is their goal?**: [e.g. Quickly deploy a hotfix, Visualize complex data]
+*   **Context**: [e.g. Running a command in a terminal on a remote server, Browsing the dashboard on a mobile device]
+
+## 2. The "Happy Path" Narrative
+
+[Write a short story (3-5 sentences) describing the perfect interaction from the user's perspective. Focus on how it *feels* - is it instant? Does it guide them?]
+
+## 3. Interface Mockups
+
+### CLI Interaction (if applicable)
+
+```bash
+# User runs this command:
+$ command --flag value
+
+# System responds immediately with:
+[ spinner ] specific loading message...
+
+# Success output:
+✅ Operation completed successfully in 1.2s
+   - Created file: /path/to/file
+   - Updated config: /path/to/config
+```
+
+### UI Layout & Flow (if applicable)
+
+**Screen/Component**: [Name]
+
+*   **Layout**: [Description of structure, e.g., "Two-column layout, left sidebar navigation..."]
+*   **Key Elements**:
+    *   **[Button Name]**: Primary action. Color: Blue.
+    *   **[Input Field]**: Placeholder text: "Enter your name...". Validation: Real-time.
+*   **States**:
+    *   **Default**: Clean state, waiting for input.
+    *   **Loading**: Skeleton loader replaces content area.
+    *   **Success**: Toast notification appears top-right: "Saved!" (Green).
+
+## 4. The "Error" Experience
+
+**Philosophy**: Don't just report the error; guide the user to the fix.
+
+### Scenario A: [Common Error, e.g. Invalid Input]
+
+*   **User Action**: Enters "123" in a text-only field.
+*   **System Response**:
+    *   (UI) Input border turns Red. Message below input: "Please enter text only."
+    *   (CLI) `❌ Error: Invalid input '123'. Expected text format.`
+*   **Recovery**: User can immediately re-type without refreshing/re-running.
+
+### Scenario B: [System Failure, e.g. Network Timeout]
+
+*   **System Response**: "Unable to connect. Retrying in 3s... (Press C to cancel)"
+*   **Recovery**: Automatic retry or explicit "Retry Now" button.
+
+## 5. Tone & Voice
+
+*   **Style**: [e.g. Concise, Technical, Friendly, Verbose]
+*   **Terminology**: [e.g. Use "Repository" not "Repo", "Directory" not "Folder"]